Did SARS-CoV-2, the novel coronavirus that causes the covid-19 disease, really start to make its deadly way around the world from Wuhan, China?
Then on Friday, 19 June, Italy’s National Institute of Health said it found genetic traces of the coronavirus in Milan and Turin’s waste water samples from back in December. This means the virus was in Italy more than two months before the first case was detected there.
The news adds to the confusion caused last month when a covid-19 infection was discovered to have sickened a patient in France on 27 December. That was nearly a month before the country’s first three confirmed coronavirus cases.
So what might the early coronavirus sightings in Italy and France really mean?
The first conclusion is straightforward enough. Clearly, the virus was in Europe almost a month earlier than previously thought.
But there is a second, more contentious possibility and it goes as follows: That covid-19 was spreading in Europe even while the focus was on Wuhan, nearly 7,000 kilometres away. Does that bolster China’s claim that it is not the pandemic’s point of origin?
Scientists offered a measured response last month when Dr Yves Cohen, head of emergency medicine at a hospital near Paris, described the case of a 43-year-old patient whose swab was tested and found positive for covid-19.
Dr Cohen said the patient, who was treated in hospital on 27 December, must have been infected between 14 and 22 December. The man recovered from the disease and was puzzled about how he caught covid-19 as he had not travelled abroad. Until that French case, the first human-to-human virus transmission within Europe was thought to have been a German man. He was infected by a Chinese colleague visiting Germany between 19 and 22 January.
But Dr Cohen suggested that his patient’s wife, who worked at a supermarket near Charles de Gaulle airport, could have come into contact with people recently arrived from China.
That didn’t seem to let China off the hook. Even so, the chatter began to increase: if the novel coronavirus were already in Europe late last year, perhaps there were different strains circulating at roughly the same time in different parts of the world?
It’s worth noting that epidemiologists have offered a cautious assessment of that particular hypothesis.
Last month, Jonathan Ball, professor of molecular virology at Nottingham University, laid out the conundrum that surrounds the stay-at-home French patient. “Whilst it was possible,” he said, “that virus could have been exported from there [Wuhan] to other parts of the world, the [French] individual in the case report hadn’t had any travel history and so would have been part of a transmission chain.” But in that case, he pointed out, “you would expect a more rapid and earlier spread of virus in France than was seen.”
Stephen Griffin, associate professor at Leeds University’s Institute of Medical Research, suggested that the French case was “a potentially important finding.” However, he counselled against jumping to conclusions. It’s necessary, he said, to “determine the viral sequence in order to track its relatedness to other SARS-COV2 sequences and to place it in context of what we know about viral evolution.” That ‘s when it will become clear if the French case “represents a genuine infection cluster.”
Expect more of the same now that Italy’s national health institute says it has proof the virus was circulating far away from China much earlier than thought.